Leafs currently have a very solid 3rd line in Komorov-Santo-Clarky. This line I personally would not touch.
Komorov doesn't seem to have the finishing touch that a top 6 player needs (that said Winnik most certainly does not).
The first line, despite being offensively gifted, is very poor defensively. You know Kessel isn't moving off that line, and Kadri-Kessel despite better corsi, is even worse defensively than JVR-Bozak-Kessel. Best keep them split up and surround them with two way players.
This is where a guy like Levio would be perfect. You don't need to give up any important Assets (Ashton and Frattin haven't really been playing anyways so cut them and if you loose them w.e), he has some size to him (6'1" 173 ibs), plays a very solid defensive game, and can contribute offensively. Booth may be a good option short term but i'd rather not get attached. He has his flaws and personally I prefer homegrown players. When Levio is cleared to play again, after a brief stint in the minors to get back to form, call him up.
This leaves just the team needing a guy like kreiji or bergeron desperately within 3 years and they could contend in the east, however serious restructuring would be needed to take on the likes of LA, Anahiem, Chicago, St. Louis, San Jose, Dallas, or Minnesota for a cup win at the present.
Line up as I would like to see:
JVR - Bozak - Kessel
>Despite lacking consistancy and having poor defensive play, until a physical two way centre falls into there lap this line likely wont improve and better options don't really exist.
Levio - Kadri - Lupul
>Both wingers are good on either side. line as a whole is very fast and on a good night will be very physical. Kadri and Lupul will pot 50 points a piece and Levio may be able to do 15G 20A as he settles in.
Komorov - Santorelli - Clarkson
>Two wingers will hit anything and everything in sight. Santorelli is a perfect combination of what Grabovski and Bolland brought to the table. Fast, dangley play maker who can utilize his wingers and play solid in his own end. Santo may not be here for the long term however, in which case a guy like Holland will need to see more ice and earn more in order to solidify this group for more than 1 season.
Winnik - Holland - Kozun/Bodie/Orr
>Winnik is a great role player, and ideally that is what the 4th line in todays NHL should be, a group of role players who are defensively responsible and can give your top guys and extra minute or two to breath. Right now it's play less than 5 mins. Part of this is because Pannik, Frattin, and Ashton are dead weight. When Booth/Levio come back ice time should increase, however Bodie is a great 4th liner who can provide energy and answer the bell should it ring and should be a rotating option for the leafs playing now. Finally I still believe that during the week until something changes to liven up the ACC or against a team like Boston or LA or any team that takes shots at guys and employs ratts like Ghallager, Marchand, Cook, Ott ect. Orr should be dressed to police it. Unlike MacLaren, Orr can actually play hockey. He is a semi-decent forechecker and an intimidating pressence on the ice. If he stays conditioned then we would have a very versatile forward group.
As mentioned, injuries to Levio/Booth, and Kozun have thinned out this roster. However in the past when guys would get hurt we would only be down to one or two lines, we are now at 2-3 lines. Team will be much deeper as guys like Broll, Brown, Carrick, Devane, Gauthier,and Mckegg, develop into serviceable NHLer's and The team is truley only two top 6 two way forwards (one who plays centre) from being a contending team in the east.